Us and Them
Natural History, November 2001
The February 15, 2001, issue of Nature was a peculiar one. Lodged in the middle of the journal was a kind of scientists’ centerfold: a multipage foldout covered in long trains of tiny hatch marks, alphanumeric codes, and squiggly graph lines. Here, for the first time in print, was a rough draft of the human genome-what Francis Collins, head of the US. Human Genome Project (HGP), called “the first glimpses of our instruction book, previously known only to God.”
It certainly gives one pause to look at this sprawling map and think about what it represents. It’s even tempting to imagine we are peering at a biological version of the soul, the unique essence that determines us both as a species and as individuals. But be careful when you turn to your genome to search for your soul. Where you expect to find your true inner self, you will come face-to— face with a mob of strangers.
Manatees With Fingernails
The New York Times Book Review
, October 14, 2001Link
A review of Aquagenesis: The Origin and Evolution of Life in the Sea
, by Richard Ellis (Viking 2001)
The history of life, on the whole, has been a soggy affair. A vast majority of Earth's creatures -- from kelp to plankton to tube worms -- has always lived in the ocean. It was probably in the ocean that life first began four billion years ago, and for billions of years after that emerged from the sea only around 360 million years ago; these recent air-breathing years have been a brief coda to our evolution.
Do Chronic Diseases Have An Infectious Root?
, September 14, 2001Link
In the 1970s, epidemiologists documented remarkably high rates of multiple sclerosis (MS) on the isolated Faeroe Islands in the North Atlantic. MS is nothing new to medicine, but it was new to the Faeroe Islands: There was no sign of it there before the 1940s. The epidemiologists found that the disease got its start during an outbreak coinciding with the arrival of British soldiers during World War II.
Natural History, September 2001
More knowledge doesn't necessarily translate into less confusion. In 1953, when James Watson and Francis Crick discovered the double-helix structure of DNA, biologists were poised for all the pieces of evolutionary theory to fall quickly into place. Darwin had shown how natural selection could transform anatomy and patterns of behavior, and now scientists looked forward to detecting the fingerprints of natural selection at the molecular level. But it turned out that natural selection was not the only force that could significantly alter DNA, and no one knew how to identify the source of any given change. It has taken decades to figure out a way.
How Old Is It?
National Geographic, September 2001 (cover story)Link
[An article about how scientists determine the age of the Earth, the galaxy, and the universe. Text to come]
The Partitioning of the Red Sea
, July 29, 2001Link
For the past 2 years, marine scientists have been engaged in a remarkable new experiment in the Red Sea. While tensions in the Middle East have escalated in the wake of renewed clashes between Israelis and Palestinians, researchers from Israel and Jordan have embarked on a long-term collaborative effort to monitor coral reefs that straddle the border between their two countries.
“Inconceivable” Bugs Eat Methane
, July 20, 2001Link
Buried in the ocean floor are more than 10 trillion tons of methane—twice the amount of all known coal, oil, and other fossil fuels. Methane (CH4) is also 25 times more potent, molecule for molecule, as a greenhouse gas than carbon dioxide is. That means that the ocean’s hidden methane reservoirs could play havoc with the world’s climate if they were to escape to the atmosphere. Yet most of the methane that does rise toward the surface of the ocean floor vanishes before it even reaches the water. On page 484 of this issue, a team of researchers provides the clinching evidence for where all that methane goes: It is devoured by vast hordes of mud-dwelling microbes that microbiologists once said couldn’t exist.
Unsafe for Any Species
The New York Times Book Review
, May 27, 2001Link
A review of The Evolution Explosion: How Humans CauseRapid Evolutionary Change
, by Stephen Palumbi (Norton, 2001)
No one set out to create dogs. When Paleolithic hunters tossed scraps of meat to some curious wolves, they didn't have a Doberman or a shar-pei in mind. And yet, by creating the conditions that favored doglike traits, our ancestors unconsciously steered their evolution. Since those early days of genetic engineering, we've become more aware of our evolutionary powers. Starting around 10,000 years ago, people began breeding and hybridizing plants and animals, selecting the traits they wanted in their cows and corn, their pigs and potatoes.
Wolbachia: A Tale of Sex and Survival
, May 11, 2001Link
On certain afternoons in Uganda, bright orange butterflies with black-and-white wings gather together on small patches of low grass, sometimes in the hundreds. Such congregations are nothing unusual in the animal kingdom; normally, males convene to try to win the attention of females. But the swarms--known as leks--that Acraea encendana form are bizarre: 94% of the butterflies are females, and they jostle for the attention of the few males, who seem reluctant suitors. "You wouldn't expect males to be surrounded by all these virgin females and not wanting to mate," says Francis Jiggins of Cambridge University. Even more bizarre is the cause of their sexual skew: They are plagued with a strain of bacteria known as Wolbachia, which kills males but spares females.
Genetic Trees Reveal Disease Origins
, May 11, 2001Link
Wendy Gibson is a paleontologist without fossils. A microbiologist at the University of Bristol, U.K., Gibson studies trypanosomes, single-celled parasites that cause sleeping sickness and related diseases. Although trypanosomes infect millions of people and countless mammals, they are as evanescent as they are common. No fossil of a trypanosome exists, and, as Gibson notes, "we can't replay history." Nevertheless, she and her colleagues have been able to reconstruct the past 100 million years of trypanosome evolution, as continents have split them apart and their hosts have evolved into new forms, including humans.
Alternative Life Styles
Natural History, May 2001
Do universal laws of evolution exist? There’s no bigger question in biology, and none harder to answer. To discover a universal rule, you need more than a single case, and when it comes to life, we’re stuck with a data set of one. All life on earth descends from a common ancestor, with every species storing its genetic information in DNA (or, in the case of some viruses, RNA). If scientists someday discover another form of life, perhaps lurking on a moon of Jupiter or in some distant solar system, they may be able to compare its evolution to our own and see if the two histories have followed the same playbook. But such an opportunity may be a long way off.
Prepared for the Past
Natural History, April 2001
Most of the time, evolution hands out its gifts sparingly. Natural selection generally produces animals that are well designed for the lives they lead—but not too well designed. Some hawks have eyes sharp enough to see a mouse up to 300 feet away, but not 1,000 miles away. After all, everything in life has a cost. An owl with eyes the size of beach balls might be able to see quite far, but it would have a hard time flying (let alone pumping enough blood to its eyes to keep them working properly). Some animals, however, do seem to be overdesigned. One of these is the American alligator (Alligator mississippiensis).
The Fine Art of Waddling
Natural History, March 2001
When Tim Griffin and Rodger Kram set out to study how penguins walk, they didn’t expect to be impressed. Compared with long-legged ostriches striding across a plain, waddling penguins come up short. Underwater they may be able to race like torpedoes in tuxedos, but on land they are more apt to evoke laughter than to inspire respect.
After You, Eve
Natural History, March 2001
My wife, Grace, and I are expecting our first child in July, so I’ve had a lot on my mind recently. Most of it has been pretty mundane stuff. What’s the fastest route from our apartment to the hospital? How exactly do you swaddle a baby? But sometimes loftier thoughts invade. I think about our child as the union of two heritages. My wife’s flows back to Ireland, to County Kerry in the south and County Derry in the north. My own heritage is more farflung, encompassing Wales, England, Germany, and Hungary, as well as countries in eastern Europe that no longer exist, having been bisected and trisected by countless wars.
Both our family trees extend back only a few generations, at which point written records and the memories of relatives fail. But we, like all other humans, also carry a genetic genealogy. Encrypted in our DNA is a history of our species. Scientists are learning how to decode that history, and they find that if you go back far enough in time, my wife’s heritage and my own eventually fuse, along with that of the rest of humanity.
Newsweek, February 5, 2001
[An article on the Galapagos Islands oil spill. Text to come]
The Perfect Limpet
Natural History, February 2001
It would seem axiomatic that well designed animals outperform badly designed ones and pass on to their offspring the genes that helped create that design. As good genes arise and spread, animal designs should theoretically shift from the flawed toward the better. So when a design is significantly inferior to what might seem best for a given situation, something interesting is probably going on. Stanford University’s Mark Denny recently investigated one such apparently poor design-that of the limpet.